Riyad us-Salihin Hadith 1032

The Messenger of Allah (ﷺ) said, "Whoever of you performs Wudu' carefully and then affirms: 'Ash-hadu an la ilaha illallahu Wahdahu la sharika Lahu, wa ash-hadu anna Muhammadan 'abduhu wa Rasuluhu [I testify that there so no true god except Allah Alone, Who has no partners and that Muhammad ((ﷺ) is His slave and Messenger],' the eight gates of Jannah are opened for him. He may enter through whichever of these gates he desires (to enter)." [Muslim]. In the narration in At- Tirmidhi, it is added: "Allahummaj-'alni minat-tawwabina, waj-'alni minal-mutatahhirin (O Allah make me among those who repent and purify themselves)."